FANCD2 genome binding is nonrandom and is enriched at large transcriptionally active neural genes prone to copy number variation.

Fanconi anemia (FA) is a rare genetic disease characterized by congenital abnormalities and increased risk for bone marrow failure and cancer. Central nervous system defects, including acute and irreversible loss of neurological function and white matter lesions with calcifications, have become increasingly recognized among FA patients, and are collectively referred to as Fanconi Anemia Neurological Syndrome or FANS. The molecular etiology of FANS is poorly understood. In this study, we have used a functional integrative genomics approach to further define the function of the FANCD2 protein and FA pathway. Combined analysis of new and existing FANCD2 ChIP-seq datasets demonstrates that FANCD2 binds nonrandomly throughout the genome with binding enriched at transcription start sites and in broad regions spanning protein-coding gene bodies. FANCD2 demonstrates a strong preference for large neural genes involved in neuronal differentiation, synapse function, and cell adhesion, with many of these genes implicated in neurodevelopmental and neuropsychiatric disorders. Furthermore, FANCD2 binds to regions of the genome that replicate late, undergo mitotic DNA synthesis (MiDAS) under conditions of replication stress, and are hotspots for copy number variation. Our analysis describes an important targeted role for FANCD2 and the FA pathway in the maintenance of large neural gene stability.

Clinical and genetic features of Fanconi anemia associated with a variant of FANCA gene: Case report and literature review.

RATIONALE: Fanconi anemia (FA) is a hereditary disease caused by mutations in the genes involved in the DNA damage repair pathway. The FANCA gene is the most commonly pathogenic gene, accounting for more than 60% of all causative genes. PATIENT CONCERNS: The clinical case is a 3-year-old boy showed mild anemia and scattered bleeding spots the size of a needle tip all over his body. DIAGNOSES: Compound heterozygous mutation was identified in the FANCA gene in the FA case: c.1A > T from the father in exon 1; the deletion of chr16: 89857810-89858476 (exon13-14 del) from the mother; finally, the patient was diagnosed as Fanconi anemia. INTERVENTION: After diagnosis, the child received chemotherapy (Ara-C + Flu + Cy + ATG). Then, the hematopoietic stem cell transplantation and unrelated umbilical cord blood transfusion were performed. OUTCOMES: The child is recovering well and is in regular follow-up. CONCLUSION AND LESSONS: The discovery of new mutations in the FANCA gene enriches the genetic profile of FA and helps clinicians to further understand this disease and guide genetic counseling and prenatal diagnosis. Whole-exome sequencing is a powerful tool for diagnosing FA.

Small pituitary volume and central nervous system anomalies in Fanconi Anemia.

Introduction: Fanconi anemia (FA) is a genomic instability disorder associated with congenital abnormalities, including short stature and the presence of central nervous system anomalies, especially in the hypothalamic-pituitary area. Thus, differences in pituitary size could associate with the short stature observed in these patients. Our aim was to evaluate whether central nervous system abnormalities and pituitary gland volume correlate with height and hormone deficiencies in these patients. Methods: In this cross-sectional exploratory study 21 patients diagnosed with FA between 2017 and 2022 in a Spanish Reference Center were investigated. Magnetic resonance imaging (MRI) was performed and pituitary volume calculated and corelated with height and other endocrine parameters. Results: The percentage of abnormalities in our series was 81%, with a small pituitary (pituitary volume less than 1 SD) being the most frequent, followed by Chiari malformation type 1. The median value of pituitary volume was -1.03 SD (IQR: -1.56, -0.36). Short stature was found in 66.7% [CI95% 43-85.4]. Total volume (mm3) increases significantly with age and in pubertal stages. There were no differences between volume SD and pubertal stage, or the presence of endocrine deficiencies. No correlations were found between pituitary volume and the presence of short stature. The intraclass correlation index (ICC) average for volume was 0.85 [CI95% 0.61-0.94] indicating a good-to-excellent correlation of measurements. Discussion: Central nervous system anomalies are part of the FA phenotype, the most frequent after pituitary hypoplasia being posterior fossa abnormalities, which may have clinical repercussions in the patient. It is therefore necessary to identify those who could be candidates for neurosurgical intervention. The size of the pituitary gland is smaller in these patients, but this does not seem to be related to hormone deficiency and short stature or exposure to a low dose of total body irradiation.

Histone-methyltransferase KMT2D deficiency impairs the Fanconi anemia/BRCA pathway upon glycolytic inhibition in squamous cell carcinoma.

Histone lysine methyltransferase 2D (KMT2D) is the most frequently mutated epigenetic modifier in head and neck squamous cell carcinoma (HNSCC). However, the role of KMT2D in HNSCC tumorigenesis and whether its mutations confer any therapeutic vulnerabilities remain unknown. Here we show that KMT2D deficiency promotes HNSCC growth through increasing glycolysis. Additionally, KMT2D loss decreases the expression of Fanconi Anemia (FA)/BRCA pathway genes under glycolytic inhibition. Mechanistically, glycolytic inhibition facilitates the occupancy of KMT2D to the promoter/enhancer regions of FA genes. KMT2D loss reprograms the epigenomic landscapes of FA genes by transiting their promoter/enhancer states from active to inactive under glycolytic inhibition. Therefore, combining the glycolysis inhibitor 2-DG with DNA crosslinking agents or poly (ADP-ribose) polymerase (PARP) inhibitors preferentially inhibits tumor growth of KMT2D-deficient mouse HNSCC and patient-derived xenografts (PDXs) harboring KMT2D-inactivating mutations. These findings provide an epigenomic basis for developing targeted therapies for HNSCC patients with KMT2D-inactivating mutations.

The role of SLFN11 in DNA replication stress response and its implications for the Fanconi anemia pathway.

Fanconi anemia (FA) is a hereditary disorder characterized by a deficiency in the repair of DNA interstrand crosslinks and the response to replication stress. Endogenous DNA damage, most likely caused by aldehydes, severely affects hematopoietic stem cells in FA, resulting in progressive bone marrow failure and the development of leukemia. Recent studies revealed that expression levels of SLFN11 affect the replication stress response and are a strong determinant in cell killing by DNA-damaging cancer chemotherapy. Because SLFN11 is highly expressed in the hematopoietic system, we speculated that SLFN11 may have a significant role in FA pathophysiology. Indeed, we found that DNA damage sensitivity in FA cells is significantly mitigated by the loss of SLFN11 expression. Mechanistically, we demonstrated that SLFN11 destabilizes the nascent DNA strands upon replication fork stalling. In this review, we summarize our work regarding an interplay between SLFN11 and the FA pathway, and the role of SLFN11 in the response to replication stress.

Oral health-related quality of life in Fanconi anemia: a cross-sectional study.

PURPOSE: To evaluate the oral health-related quality of life (OHRQoL) of individuals diagnosed with Fanconi anemia (FA). METHODS: A cross-sectional study was conducted with FA patients from two Brazilian referral centers. Participants underwent a complete dental, periodontal, and oral mucosa examination, as well as assessment of resting salivary flow. The short version of the Oral Health Impact Profile (OHIP-14) questionnaire was administered. Descriptive and bivariate analyses were performed, followed by multivariate analysis to examine the impact of independent variables on OHRQoL. RESULTS: The study included 20 (57.1%) males and 15 (42.9%) females, with a mean age of 18.9 years. Oral leukoplakia (OL) was found in 18 individuals. The overall OHIP-14 score was 9.9 ± 10.5. Individuals aged ≥ 16 years had higher OHIP-14 scores, indicating worse OHRQoL for physical pain (p = 0.007), psychological discomfort (p = 0.001), physical disability (p = 0.03), psychological disability (p = 0.001), handicap (p = 0.004), and overall score (p = 0.007). Females reported more negative OHRQoL than males for physical pain (p = 0.02), psychological discomfort (p = 0.03), psychological disability (p = 0.009), and overall score (p = 0.02). Individuals with OL had an overall OHIP-14 score 1.83 times higher than those without OL (95% CI: 1.02-3.28; p = 0.04). Lower salivary flow correlated with higher overall OHIP-14 scores (95% CI: 0.14-0.84; p = 0.01). CONCLUSION: This study represents the first attempt to evaluate OHRQoL in individuals with FA. The presence of OL and reduced salivary flow were identified as predictors of a negative impact on OHRQoL. It is imperative to integrate patients' quality of life in the clinical treatment protocols for the FA population.

The Fanconi anemia core complex promotes CtIP-dependent end resection to drive homologous recombination at DNA double-strand breaks.

During the repair of interstrand crosslinks (ICLs) a DNA double-strand break (DSB) is generated. The Fanconi anemia (FA) core complex, which is recruited to ICLs, promotes high-fidelity repair of this DSB by homologous recombination (HR). However, whether the FA core complex also promotes HR at ICL-independent DSBs, for example induced by ionizing irradiation or nucleases, remains controversial. Here, we identified the FA core complex members FANCL and Ube2T as HR-promoting factors in a CRISPR/Cas9-based screen. Using isogenic cell line models, we further demonstrated an HR-promoting function of FANCL and Ube2T, and of their ubiquitination substrate FANCD2. We show that FANCL and Ube2T localize at DSBs in a FANCM-dependent manner, and are required for the DSB accumulation of FANCD2. Mechanistically, we demonstrate that FANCL ubiquitin ligase activity is required for the accumulation of CtIP at DSBs, thereby promoting end resection and Rad51 loading. Together, these data demonstrate a dual genome maintenance function of the FA core complex and FANCD2 in promoting repair of both ICLs and DSBs.

Fanconi Anaemia associated with café au lait spots: A rare case report.

Fanconi Anaemia is an autosomal recessive disorder, which is characterised by progressive pancytopenia, café au lait spots (>50%), bruising, petechie, recurrent infections, short height (50%), and thumb and radial bone anomalies (40%). Herein, is presented a case of a lean emaciated female child, who presented with the chief complaints of fever, loose stools and decreased appetite for one month reported at Sindh Government General Hospital, Karachi, on February, 1, 2023. She had cutaneous findings of hyperpigmentation and café au lait spots and a tri-phalangeal thumb. On investigation, pancytopenia and a low reticulocyte count of 0.7% was also observed. Karyotype and chromosomal breakage test induced by Diepoxybutane confirmed her as a case of Fanconi Anaemia.

Outcomes of hematopoietic stem cell transplantation in 813 pediatric patients with Fanconi anemia.

ABSTRACT: Allogeneic hematopoietic stem cell transplantation (HSCT) is the only established curative option for Fanconi anemia (FA)-associated bone marrow failure (BMF)/aplastic anemia (AA) and acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS). We performed a retrospective multicenter study on 813 children with FA undergoing first HSCT between 2010 and 2018. Median duration of follow-up was 3.7 years. Median age at transplant was 8.8 years (IQR, 6.5-18.1). Five-year overall survival (OS), event-free survival (EFS), and graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS) were 83% (95% confidence interval [CI], 80-86), 78% (95% CI, 75-81), and 70% (95% CI, 67-74), respectively. OS was comparable between matched family donor (MFD; n = 441, 88%) and matched unrelated donor (MUD; n = 162, 86%) and was superior to that of mismatched family donor (MMFD) or mismatched unrelated donor (MMUD; n = 144, 72%) and haploidentical donor (HID; n = 66, 70%; P < .001). In multivariable analysis, a transplant indication of AML/MDS (vs AA/BMF), use of MMFD/MMUD and HID (vs MFD), and fludarabine-cyclophosphamide (FluCy) plus other conditioning (vs FluCy) independently predicted inferior OS, whereas alemtuzumab vs antithymocyte globulin was associated with better OS. Age ≥10 years was associated with worse EFS and GRFS. Cumulative incidences (CINs) of primary and secondary graft failure were 2% and 3% respectively. CINs of grade 3 to 4 acute GVHD and chronic GVHD were 12% and 8% respectively. The 5-year CIN of secondary malignancy was 2%. These data suggest that HSCT should be offered to patients with FA with AA/BMF at a younger age in the presence of a well-matched donor.

The splicing factor CCAR1 regulates the Fanconi anemia/BRCA pathway.

The twenty-three Fanconi anemia (FA) proteins cooperate in the FA/BRCA pathway to repair DNA interstrand cross-links (ICLs). The cell division cycle and apoptosis regulator 1 (CCAR1) protein is also a regulator of ICL repair, though its possible function in the FA/BRCA pathway remains unknown. Here, we demonstrate that CCAR1 plays a unique upstream role in the FA/BRCA pathway and is required for FANCA protein expression in human cells. Interestingly, CCAR1 co-immunoprecipitates with FANCA pre-mRNA and is required for FANCA mRNA processing. Loss of CCAR1 results in retention of a poison exon in the FANCA transcript, thereby leading to reduced FANCA protein expression. A unique domain of CCAR1, the EF hand domain, is required for interaction with the U2AF heterodimer of the spliceosome and for excision of the poison exon. Taken together, CCAR1 is a splicing modulator required for normal splicing of the FANCA mRNA and other mRNAs involved in various cellular pathways.

Splicing regulation of DNA repair via CCAR1.

In this issue of Molecular Cell, Harada et al.1 and Karasu et al.2 identify CCAR1 as a novel regulator of the Fanconi anemia/BRCA DNA repair pathway via modulating the splicing of the mRNA encoding FANCA.

CCAR1 promotes DNA repair via alternative splicing.

DNA repair is directly performed by hundreds of core factors and indirectly regulated by thousands of others. We massively expanded a CRISPR inhibition and Cas9-editing screening system to discover factors indirectly modulating homology-directed repair (HDR) in the context of ∼18,000 individual gene knockdowns. We focused on CCAR1, a poorly understood gene that we found the depletion of reduced both HDR and interstrand crosslink repair, phenocopying the loss of the Fanconi anemia pathway. CCAR1 loss abrogated FANCA protein without substantial reduction in the level of its mRNA or that of other FA genes. We instead found that CCAR1 prevents inclusion of a poison exon in FANCA. Transcriptomic analysis revealed that the CCAR1 splicing modulatory activity is not limited to FANCA, and it instead regulates widespread changes in alternative splicing that would damage coding sequences in mouse and human cells. CCAR1 therefore has an unanticipated function as a splicing fidelity factor.

A Nutrigenomic View on the Premature-Aging Disease Fanconi Anemia.

Fanconi anemia, a rare disorder with an incidence of 1 in 300,000, is caused by mutations in FANC genes, which affect the repair of DNA interstrand crosslinks. The disease is characterized by congenital malformations, bone marrow failure within the first decade of life, and recurrent squamous cell carcinomas of the oral cavity, esophagus, and anogenital regions starting around age 20. In this review, we propose that Fanconi anemia should be considered a premature-aging syndrome. Interestingly, the onset and severity of the life-limiting clinical features of Fanconi anemia can be influenced by lifestyle choices, such as a healthy diet and physical activity. These factors shape the epigenetic status of at-risk cell types and enhance the competence of the immune system through nutritional signaling. Fanconi anemia may serve as a model for understanding the aging process in the general population, addressing research gaps in its clinical presentation and suggesting prevention strategies. Additionally, we will discuss how the balance of genetic and environmental risk factors-affecting both cancer onset and the speed of aging-is interlinked with signal transduction by dietary molecules. The underlying nutrigenomic principles will offer guidance for healthy aging in individuals with Fanconi anemia as well as for the general population.

Advanced Analysis and Validation of a microRNA Signature for Fanconi Anemia.

Some years ago, we reported the generation of a Fanconi anemia (FA) microRNA signature. This study aims to develop an analytical strategy to select a smaller and more reliable set of molecules that could be tested for potential benefits for the FA phenotype, elucidate its biochemical and molecular mechanisms, address experimental activity, and evaluate its possible impact on FA therapy. In silico analyses of the data obtained in the original study were thoroughly processed and anenrichment analysis was employed to identify the classes of genes that are over-represented in the FA-miRNA population under study. Primary bone marrow mononuclear cells (MNCs) from sixFA patients and sixhealthy donors as control samples were employed in the study. RNAs containing the small RNA fractions were reverse-transcribed and real-time PCR was performed in triplicate using the specific primers. Experiments were performed in triplicate.The in-silico analysis reported six miRNAs as likely contributors to the complex pathological spectrum of FA. Among these, three miRNAs were validated by real-time PCR. Primary bone marrow mononuclear cells (MNCs) reported a significant reduction in the expression level of miRNA-1246 and miRNA-206 in the FA samples in comparison to controls.This study highlights several biochemical pathways as culprits in the phenotypic manifestations and the pathophysiological mechanisms acting in FA. A relatively low number of miRNAs appear involved in all these different phenotypes, demonstrating the extreme plasticity of the gene expression modulation. This study further highlights miR-206 as a pivotal player in regulatory functions and signaling in the bone marrow mesenchymal stem cell (BMSC) process in FA. Due to this evidence, the activity of miR-206 in FA deserves specific experimental scrutiny. The results, here presented, might be relevant in the management of FA.

Fanconi Anemia in a 31-Year-Old Patient with Multiple Malignant Tumor Foci, Including Appendiceal Cancer, and Multiple Coexisting Pathologies.

BACKGROUND Fanconi anemia (FA) is a genetic disorder that impairs the function of the bone marrow and predisposes individuals to aplastic anemia. The condition is caused by mutations in genes responsible for DNA repair. People with FA have an increased risk of developing tumors due to DNA damage. Flat-cell carcinomas of the head, neck, esophagus, and genital organs are often observed in individuals with FA. CASE REPORT A 31-year-old man with Fanconi anemia and a history of bone marrow transplantation was admitted to the General Surgery Department due to elevated levels of the CEA marker. Before the transplantation, chromosomal anomalies, bone marrow hypoplasia, kidney agenesis, and bone defects were noted. After the transplantation, he developed a skin rash. He was also diagnosed with squamous cell carcinoma of the lip and chronic conditions, including cholestatic liver damage, hypertension, and hypothyroidism. During the diagnostic process, computed tomography showed signs of Barrett's esophagus, numerous polyps in the stomach and intestines, and a nodular formation measuring 4.5×5×5.5 cm in the right iliac region. Laparoscopy revealed a neoplasm of the appendix with numerous metastases on the inner abdominal wall and omentum. Histological analysis confirmed mucinous appendiceal cancer. The patient was discharged for palliative treatment at the Oncology Center with a final diagnosis of appendiceal cancer, mucinous type, grade G3. This case underscores the importance of early and comprehensive cancer screening in individuals with FA, particularly those with a history of bone marrow transplantation. CONCLUSIONS This clinical case underscores the critical importance of thorough and timely cancer diagnosis in individuals with this genetic pathology.

In Fanconi anemia, impaired accumulation of bone marrow neutrophils during emergency granulopoiesis induces hematopoietic stem cell stress.

Fanconi anemia (FA) is an inherited disorder of DNA repair due to mutation in one of 20+ interrelated genes that repair intrastrand DNA crosslinks and rescue collapsed or stalled replication forks. The most common hematologic abnormality in FA is anemia, but progression to bone marrow failure (BMF), clonal hematopoiesis, or acute myeloid leukemia may also occur. In prior studies, we found that Fanconi DNA repair is required for successful emergency granulopoiesis; the process for rapid neutrophil production during the innate immune response. Specifically, Fancc-/- mice did not develop neutrophilia in response to emergency granulopoiesis stimuli, but instead exhibited apoptosis of bone marrow hematopoietic stem cells and differentiating neutrophils. Repeated emergency granulopoiesis challenges induced BMF in most Fancc-/- mice, with acute myeloid leukemia in survivors. In contrast, we found equivalent neutrophilia during emergency granulopoiesis in Fancc-/-Tp53+/- mice and WT mice, without BMF. Since termination of emergency granulopoiesis is triggered by accumulation of bone marrow neutrophils, we hypothesize neutrophilia protects Fancc-/-Tp53+/- bone marrow from the stress of a sustained inflammation that is experienced by Fancc-/- mice. In the current work, we found that blocking neutrophil accumulation during emergency granulopoiesis led to BMF in Fancc-/-Tp53+/- mice, consistent with this hypothesis. Blocking neutrophilia during emergency granulopoiesis in Fancc-/-Tp53+/- mice (but not WT) impaired cell cycle checkpoint activity, also found in Fancc-/- mice. Mechanisms for loss of cell cycle checkpoints during infectious disease challenges may define molecular markers of FA progression, or suggest therapeutic targets for bone marrow protection in this disorder.

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Objective: Infertility affects approximately one-sixth of the people of childbearing age worldwide, causing not only economic burdens of treatment for families with fertility problems but also psychological stress for patients and presenting challenges to societal and economic development. Premature ovarian insufficiency (POI) refers to the loss of ovarian function in women before the age of 40 due to the depletion of follicles or decreased quality of remaining follicles, constituting a significant cause of female infertility. In recent years, with the help of the rapid development in genetic sequencing technology, it has been demonstrated that genetic factors play a crucial role in the onset of POI. Among the population suffering from POI, genetic studies have revealed that genes involved in processes such as meiosis, DNA damage repair, and mitosis account for approximately 37.4% of all pathogenic and potentially pathogenic genes identified. FA complementation group M (FANCM) is a group of genes involved in the damage repair of DNA interstrand crosslinks (ICLs), including FANCA-FANCW. Abnormalities in the FANCM genes are associated with female infertility and FANCM gene knockout mice also exhibit phenotypes similar to those of POI. During the genetic screening of POI patients, this study identified a suspicious variant in FANCM. This study aims to explore the pathogenic mechanisms of the FANCM genes of the FA pathway and their variants in the development of POI. We hope to help shed light on potential diagnostic and therapeutic strategies for the affected individuals. Methods: One POI patient was included in the study. The inclusion criteria for POI patients were as follows: women under 40 years old exhibiting two or more instances of basal serum follicle-stimulating hormone levels>25 IU/L (with a minimum interval of 4 weeks inbetween tests), alongside clinical symptoms of menstrual disorders, normal chromosomal karyotype analysis results, and exclusion of other known diseases that can lead to ovarian dysfunction. We conducted whole-exome sequencing for the POI patient and identified pathogenic genes by classifying variants according to the standards and guidelines established by the American College of Medical Genetics and Genomics (ACMG). Subsequently, the identified variants were validated through Sanger sequencing and subjected to bioinformatics analysis. Plasmids containing wild-type and mutant FANCM genes were constructed and introduced into 293T cells. The 293T cells transfected with wild-type and mutant human FANCM plasmids and pEGFP-C1 empty vector plasmids were designated as the EGFP FANCM-WT group, the EGFP FANCM-MUT group, and the EGFP group, respectively. To validate the production of truncated proteins, cell proteins were extracted 48 hours post-transfection from the three groups and confirmed using GFP antibody. In order to investigate the impact on DNA damage repair, immunofluorescence experiments were conducted 48 hours post-transfection in the EGFP FANCM-WT group and the EGFP FANCM-MUT group to examine whether the variant affected FANCM's ability to localize on chromatin. Mitomycin C was used to induce ICLs damage in vitro in both the EGFP FANCM-WT group and the EGFP FANCM-MUT group, which was followed by verification of its effect on ICLs damage repair using γ-H2AX antibody. Results: In a POI patient from a consanguineous family, we identified a homozygous variant in the FANCM gene, c.1152-1155del:p.Leu386Valfs*10. The patient presented with primary infertility, experiencing irregular menstruation since menarche at the age of 16. Hormonal evaluation revealed an FSH level of 26.79 IU/L and an anti-Müllerian hormone (AMH) level of 0.07 ng/mL. Vaginal ultrasound indicated unsatisfactory visualization of the ovaries on both sides and uterine dysplasia. The patient's parents were a consanguineous couple, with the mother having regular menstrual cycles. The patient had two sisters, one of whom passed away due to osteosarcoma, while the other exhibited irregular menstruation, had been diagnosed with ovarian insufficiency, and remained childless. Bioinformatics analysis revealed a deletion of four nucleotides (c.1152-1155del) in the exon 6 of the patient's FANCM gene. This variant resulted in a frameshift at codon 386, introducing a premature stop codon at codon 396, which ultimately led to the production of a truncated protein consisting of 395 amino acids. In vitro experiments demonstrated that this variant led to the production of a truncated FANCM protein of approximately 43 kDa and caused a defect in its nuclear localization, with the protein being present only in the cytoplasm. Following treatment with mitomycin C, there was a significant increase in γ-H2AX levels in 293T cells transfected with the mutant plasmid (P<0.01), indicating a statistically significant impairment of DNA damage repair capability caused by this variant. Conclusions: The homozygous variant in the FANCM gene, c.1152-1155del:p.Leu386Valfs*10, results in the production of a truncated FANCM protein. This truncation leads to the loss of its interaction site with the MHF1-MHF2 complex, preventing its entry into the nucleus and the subsequent recognition of DNA damage. Consequently, the localization of the FA core complex on chromatin is disrupted, impeding the normal activation of the FA pathway and reducing the cell's ability to repair damaged ICLs. By disrupting the rapid proliferation and meiotic division processes of primordial germ cells, the reserve of oocytes is depleted, thereby triggering premature ovarian insufficiency in females.